chore: modifying public interfaces and adding an integration test.

google-cloud-spanner/src/main/java/com/google/cloud/spanner/Spanner.java

@@ -18,8 +18,6 @@
 
 import com.google.api.gax.core.ExecutorProvider;
 import com.google.cloud.Service;
-import com.google.cloud.spanner.admin.database.v1.DatabaseAdminSettings;
-import com.google.cloud.spanner.admin.instance.v1.InstanceAdminSettings;
 
 /**
  * An interface for Cloud Spanner. Typically, there would only be one instance of this for the
@@ -42,11 +40,9 @@ public interface Spanner extends Service<SpannerOptions>, AutoCloseable {
 
   /**
    *
-   * @param settings
    * @return
    */
-  com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient getDatabaseAdminClient(
-      DatabaseAdminSettings... settings);
+  com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient databaseAdminClient();
 
   /** Returns an {@code InstanceAdminClient} to do admin operations on Cloud Spanner instances. */
   /*
@@ -62,11 +58,9 @@ com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient getDatabaseAdminC
 
   /**
    *
-   * @param settings
    * @return
    */
-  com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient getInstanceAdminClient(
-      InstanceAdminSettings... settings);
+  com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient instanceAdminClient();
 
 
   /**

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java

@@ -27,12 +27,9 @@
 import com.google.cloud.spanner.SpannerOptions.CloseableExecutorProvider;
 import com.google.cloud.spanner.admin.database.v1.DatabaseAdminSettings;
 import com.google.cloud.spanner.admin.database.v1.stub.DatabaseAdminStub;
-import com.google.cloud.spanner.admin.database.v1.stub.DatabaseAdminStubSettings;
-import com.google.cloud.spanner.admin.database.v1.stub.GrpcDatabaseAdminStub;
 import com.google.cloud.spanner.admin.instance.v1.InstanceAdminSettings;
 import com.google.cloud.spanner.admin.instance.v1.stub.GrpcInstanceAdminStub;
 import com.google.cloud.spanner.admin.instance.v1.stub.InstanceAdminStub;
-import com.google.cloud.spanner.admin.instance.v1.stub.InstanceAdminStubSettings;
 import com.google.cloud.spanner.spi.v1.GapicSpannerRpc;
 import com.google.cloud.spanner.spi.v1.SpannerRpc;
 import com.google.cloud.spanner.spi.v1.SpannerRpc.Paginated;
@@ -47,6 +44,7 @@
 import io.opencensus.metrics.LabelValue;
 import io.opencensus.trace.Tracer;
 import io.opencensus.trace.Tracing;
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -201,25 +199,9 @@ public DatabaseAdminClient getDatabaseAdminClient() {
   }
 
   @Override
-  public com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient getDatabaseAdminClient(
-      DatabaseAdminSettings... settings) {
-    if(settings.length != 0) {
-      com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient client =
-          com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient.create(
-              Arrays.stream(settings).iterator().next());
-      return client;
-    } else {
-      DatabaseAdminStub databaseAdminStub =
-          GrpcDatabaseAdminStub.create(
-              getOptions()
-                  .getDatabaseAdminStubSettings()
-                  .toBuilder()
-                  .setTransportChannelProvider(channelProvider)
-                  .setCredentialsProvider(credentialsProvider)
-                  .setStreamWatchdogProvider(watchdogProvider)
-                  .build());
-      return com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient.create(databaseAdminStub);
-    }
+  public com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient databaseAdminClient() {
+    DatabaseAdminStub databaseAdminStub = gapicRpc.getDatabaseAdminStub();
+    return com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient.create(databaseAdminStub);
   }
 
   @Override
@@ -228,24 +210,9 @@ public InstanceAdminClient getInstanceAdminClient() {
   }
 
   @Override
-  public com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient getInstanceAdminClient(
-      InstanceAdminSettings... settings) {
-    if(settings.length != 0) {
-      com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient client =
-          com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient.create(Arrays.stream(settings).iterator().next());
-      return client;
-    } else {
-      InstanceAdminStub instanceAdminStub =
-          GrpcInstanceAdminStub.create(
-              getOptions()
-                  .getInstanceAdminStubSettings()
-                  .toBuilder()
-                  .setTransportChannelProvider(channelProvider)
-                  .setCredentialsProvider(credentialsProvider)
-                  .setStreamWatchdogProvider(watchdogProvider)
-                  .build());
-      return com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient.create(instanceAdminStub);
-    }
+  public com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient instanceAdminClient() {
+    InstanceAdminStub instanceAdminStub = gapicRpc.getInstanceAdminStub();
+    return com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient.create(instanceAdminStub);
   }
 
   @Override

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpc.java

@@ -2058,4 +2058,14 @@ private static Duration systemProperty(String name, int defaultValue) {
     String stringValue = System.getProperty(name, "");
     return Duration.ofSeconds(stringValue.isEmpty() ? defaultValue : Integer.parseInt(stringValue));
   }
+
+  @Override
+  public DatabaseAdminStub getDatabaseAdminStub() {
+    return databaseAdminStub;
+  }
+
+  @Override
+  public InstanceAdminStub getInstanceAdminStub() {
+    return instanceAdminStub;
+  }
 }

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/SpannerRpc.java

@@ -497,4 +497,21 @@ TestIamPermissionsResponse testInstanceAdminIAMPermissions(
   void shutdown();
 
   boolean isClosed();
+
+  /**
+   *
+   * @return
+   */
+  default InstanceAdminStub getInstanceAdminStub() {
+    throw new UnsupportedOperationException("Not implemented");
+  }
+
+  /**
+   *
+   * @return
+   */
+  default DatabaseAdminStub getDatabaseAdminStub() {
+    throw new UnsupportedOperationException("Not implemented");
+  }
+
 }